1. Field of the Invention
The present invention relates to a record control apparatus for controlling to write record data in a buffer which stores the record data to be recorded with a recording head of a serial scan type.
2. Related Background Art
A recording apparatus such as a printer has a recording head constituted of a plurality of recording elements of a dot impact type, a thermal type or an ink jet type. Record data is generally printed by a serial scan method. Namely, record data is printed while the recording head is moved along a direction perpendicular to the transport direction of a recording sheet. After one row is printed, the recording sheet is transported by an amount corresponding to the width of the recording head. This operation is repeated.
The record data corresponding in amount to the width of a recording head is sequentially supplied to the recording head. The recording elements are driven each time the recording head moves by a distance corresponding to one pixel to thereby form a record image.
[Conventional Data Storage Process 1]
FIG. 19 is a schematic diagram illustrating a record operation by a recording head of a recording apparatus of this type.
As shown in FIG. 19, the recording head can print thirty-two vertical dots at the same time. One row is constituted of 1024 dots in a maximum recordable size of a record sheet.
Conventionally, record data is stored in a storage device such as a DRAM at addresses such as shown in FIG. 20.
FIG. 20 is a memory map of a storage medium for storing record data to be recorded with a recording apparatus of this type. Record data provided through a drive such as an interface is often transferred in the order of a scanning direction of the recording head, so that it is stored in the storage medium at horizontally consecutive addresses.
In this example shown in FIG. 20, bandlike data of 8 vertical bits for the first row is stored at addresses from “OOOOH” to “03FFH” by the amount corresponding to horizontal 1024 bits. Bandlike data of 8 vertical bits for the next row is stored at addresses from “0400H” to “07FFH” by the amount corresponding to 1024 horizontal bits.
Such bandlike data is sequentially stored in a print buffer memory having a capacity of 5120 bytes at addresses from “0000H” to “13FFH”. Therefore, after bandlike data of five rows is stored, the next data cannot be stored in the buffer memory.
The vertical width of the recording head is 32 dots and can record bandlike data of four rows at the same time. Therefore, bandlike data is sequentially read starting from the start addresses “0000H”, “0400H”, “0800H” and “0C00H”, and each time the recording head moves by an amount corresponding to one pixel, bandlike data is read at the addresses incremented by “1”. In this manner, four memory bands are controlled to read bandlike data.
More specifically, bandlike data is read from addresses “0000H”, “0400H”, “0800H” and “0C00H”, and after the recording head moves by one pixel amount, bandlike data is read from addresses “000H”, “0401H”, “0801H” and “0C01H”. This data read process is performed up to the addresses “03FFH”, “07FFH”, “0BFFH” and “0FFFH” to complete data read of one scan.
After the recording head is scanned once, the buffer memory becomes empty by the amount corresponding to four bands and the next data can be supplied from the interface and stored starting from the address “0000H”.
After the data of the four bands is stored in the buffer memory, the recording head records bandlike data starting from the start addresses “1000H”, “0000H”, “0400H” and “0800H”, and each time the recording head moves by an amount corresponding to one pixel, bandlike data is read at the addresses incremented by “1”.
[Conventional Data Storage Process 2]
In the memory address storing method according to the above-described conventional data storage process 1, sequentially read memory addresses are not continuous so that memory access in a fast page mode of DRAM is not possible. If a scan speed is relatively slow, a memory access in the fast page mode is not necessary. However, it is essential for a fast speed and high density record system to use the fast page mode memory access.
It is therefore necessary to store bandlike data at addresses sequentially incrementing by “1” in the order of data read. Conventionally, as shown in FIG. 21, bandlike data is stored by rearranging the addresses in the order of data read.
FIG. 21 is a memory map of another storage medium for storing record data to be recorded with a recording apparatus of this type. In order to improve the print quality, the same data is divided and stored for a plurality of passes. At the first pass, record data is read from addresses “0000H”, “0001H”, “0002H” and “0003H” and each time the recording head moves by a distance corresponding to one pixel, record data is read at addresses sequentially incremented by “1” as “0004H”, “0005H”, “0006H” and “0007H”. However, at the second pass, record date is read at addresses not continuous as “0001H”, “0002H”, “0003H” and “1000H”. Therefore, the fast page mode data transfer is frequently interrupted.
Similar to the conventional data storage process 1, an address generation block for managing a plurality of memory bands is necessary, which results in a large circuit scale.